Octanoic acid, esters with anhydrosorbitol and dianhydrosorbitol

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1996-12-11

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Sorbitanmonococoat is the C12-C14 C chain homologue of the C8 Sorbitanmonocaprylate. Usually toxicity to microorganisms is higher with longer C chain length. Read-across from Sorbitanmonococoat is most likely a worst case approach. The test follows the OECD 209 Guideline. Raw data are not reported but this procedure was not uncommon at that time.Due to this fact a 'reliable with restrictions' is assigned.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sorbitanmonococoate

IUPAC Name:

Sorbitanmonococoate

Details on test material:

- Name of test material (as cited in study report): Sorbitanmonococoat
- Physical state: Liquid, colourless
- Lot/batch No.: 8/96
- Expiration date of the lot/batch: 1997-10-01
- Storage condition of test material: Room temperature, protected from light, in original container.

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:direct weighing
- Eluate: Synthetic waste water according to OECD Guidelinie 209
- Differential loadings: 100 - 320 - 1000 - 3200 - 10000 mg/L
- Controls: Test medium without test or reference item.

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

- Preparation of inoculum for exposure: Non adapted activated sludge from the sewage plant at Hildesheim (Municipal sewage treatment plant of Hildesheim, Germany)
- Pretreatment: Washed twice with chlorine free tap water. Adjustment to a dry sludge concentration of 3.0 g/L ± 10 % was not necessary. The sludge was used within 24 h after sampling.

Dry weight activated sludge: 3.2 g/L

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Hardness:

Not determined

Test temperature:

20 °C

pH:

pH-value of the activated sludge 7.08

Salinity:

Not determined

Nominal and measured concentrations:

100 - 320 - 1000 - 3200 - 10000 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL Erlenmeyer flask
- Aeration: Shaking of flasks at 150 rpm to keep the dissolved oxygen concentration above 60 - 70 % saturation and to maintain the sludge flakes in suspension.
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
After 3 h incubation, the oxygen concentration of each control, reference item and test item replicate was determined by means of oximeter immediately after transfering the solution to the measuring cell and the oxygen depletion was recorded for at least 3 minutes on a flatbed recorder.

Reference substance (positive control):

yes

Remarks:

Copper (II) sulphate pentahydrate p.a.

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

1 696 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 95% CI (1404-2048 mg/L)

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: None

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: EC50: 107 mg/L

Reported statistics and error estimates:

The NOEC was determined by calculation of statistical significance of the inhibition of respiration in comparison to the control. One Way Analysis of Variance (ANOVA) and DUNNETT’s test was used for NOEC calculations. When running a One Way Analysis of Variance a Normality test and an Equal Variance test were done first. P-values for both Normality and Equal Variance test are 0.05. The a-value (acceptable probability of incorrectly concluding that there is a difference) is a=0.05.

The EC-values of the test item and the reference item were calculated by linear regression using software GraphPadPrism. Calculations of the confidence intervals for the EC-values were carried out using standard procedures.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC50 of Sorbitanmonococoat is 1696 mg/L. Sorbitancocoat is not toxic up to the concentration of 417mg/L (EC20) to activated sludge of a municipal sewage treatment plant.